As such a vehicle air-conditioning unit, an air conditioning unit included in a vehicle air-conditioning unit described in Patent Literature 1. The air conditioning unit described in Patent Literature 1 has two openings and a rotary door that opens and closes one opening of the two openings. The other opening of the two openings is not opened and closed by the rotary door and is constantly open.
The rotary door has a rotary shaft located between the two openings. The rotary door has a notch at a location adjacent to the rotary shaft and corresponding to the other opening so as not to close the other opening regardless of positions of the rotary door.
When the rotary door closes the one opening, the notch provides a recessed portion. A wind direction adjustment plate, protruding from an air conditioning case and located corresponding to the notch, covers the recessed portion such that the conditioning air does not flow round to the recessed portion. The wind direction adjustment plate is provided integrally with the air conditioning case.
According to Patent Literature 1, air flows into the other opening smoothly, thereby a turbulence flow of air is suppressed and a generation of low-frequency muffled sound (i.e., noise) can be suppressed.